In this episode Shahriar investigates a faulty Agilent 53152A 46GHz frequency counter. The instrument does not power on and shows no sign of internal voltage presence. Teardown of the instrument reveals a large PCB where all analog and digital circuity is contained. The power supply module is a module components and upon measurements shows no activity.
The power supply is a simple switching architecture with functioning input rectifier and capacitor filter. By using an oscilloscope it is clear that the power supply PWM controller attempts to start. However, the main power supply pin shows unstable voltages indicating inadequate charge retention on the rectifying capacitor. Replacing the capacitor revives the startup condition and the power supply function returns. The PWM controller and main switching transistors are also replaced with new ones. After this repair the unit powers on and passes all self-tests. The unit can successfully measure signal frequencies and power.
In this short episode Shahriar demonstrates an overview of the new Tektronix MSO58 8-Channel 6.25GS/s 2GHz Mixed-Signal Oscilloscope with up to 64-Bits of digital channels. The scope features independent ADC, data acquisition and memory per channel as well as FlexChannel architecture which allows each channel to act as either a 2GHz analog channel or an 8-Bit digital channel. The scope also features a brand new GUI interface on an HD 15.6″ display with significant performance enhancement and touch interface optimizations. A full review of the instrument will be provided in the future.
In this episode Shahriar explores the principle operation of automotive FMCW radars. Thanks to a donated automotive radar module, various components of the system can be examined and explored. The PCB reveals three die-on-PCB ASICs responsible for generating and receiving 77GHz FMCW signals coupled to a 2D array of antennas. Several microwave components such as rat-race couplers and branchline couplers can also be observed. PCB rulers from SV1AFN Design Lab also show these microwave components at much lower frequencies. Two other ICs are used for ramp generation and PLL as well as a multi-input LNA/PGA/AAF with 12-bit ADC for IF processing. All components are examined under the microscope and the frequency of operation is calculated by measuring the branchline coupler’s dimensions.
Finally a simple Doppler effect radar is constructed by using a doubler, power divider, mixer and a pair of Vivaldi horn antennas. The Doppler effect can be observed by moving an object in front of the antenna pair.
In this episode Shahriar reviews the Tektronix RSA607A real-time spectrum analyzer which operates from 9kHz to 7.5GHz. The instrument has a 40MHz wide analysis window with a DANL of -160dBm. The built-in tracking generator is capable of measuring return loss, cable loss and DTF measurements without a need for an external coupler. This review is organized as follows:
01:03 – Model comparison and overview.
03:25 – Front & rear panel overview.
05:31 – Complete unit teardown & examination.
16:33 – Reverse engineering and experiments with a drone remote control transmitter.
39:27 – Characterizing and experimenting with an ISM band diplexer.
47:29 – Return loss measurements of a tunable band-pass filter.
53:23 – Concluding remarks.
In this episode Shahriar reviews the Deepace KC901V 6.8GHz handheld network analyzer. This battery-powered instrument is an RF multi-instrument integrating VNA, spectrum analyzer, field strength meter, and a low-frequency signal generator. It can also perform signal port vector measurement and 2-ports simple vector network analyzing (S11, S21). The review is organized as follows:
01:24 – Instrument overview & block diagram.
05:36 – Full teardown along with RF and digital board analysis.
14:30 – Power on, calibration and S11 measurement of an antenna.
23:46 – Calibration for S21 and measurement of a tunable filter plus phase shifter.
32:23 – Distance to fault measurement of an SMA cable chain.
36:24 – Spectrum analyzer measurements and limitations.
43:16 – Signal generator measurements and issues.
48:20 – Other features and concluding remarks.
50:07 – Giveaway!
The Signal Path (TSP) is an electrical engineering video blog for industry professionals, students and hobbyists. TSP is a non-for-profit website dedicated to provide free education spanning a wide range of electrical engineering topics. Equipment reviews, tutorials and repair videos are posted regularly.